RESUMO
Mutations in the GNAO1 gene, which encodes the abundant brain G-protein Gαo, result in neurologic disorders characterized by developmental delay, epilepsy, and movement abnormalities. There are over 50 mutant alleles associated with GNAO1 disorders; the R209H mutation results in dystonia, choreoathetosis, and developmental delay without seizures. Mice heterozygous for the human mutant allele (Gnao1 +/R209H) exhibit hyperactivity in open field tests but no seizures. We developed self-complimentary adeno-associated virus vectors (scAAV9) expressing two splice variants of human GNAO1 Gαo isoforms 1 (GoA, GNAO1.1) and 2 (GoB, GNAO1.2). Bilateral intra-striatal injections of either scAAV9-GNAO1.1 or scAAV9-GNAO1.2 significantly reversed mutation-associated hyperactivity in open field tests. GNAO1 overexpression did not increase seizure susceptibility, a potential side-effect of GNAO1 vector treatment. This represents the first report of successful preclinical gene therapy for GNAO1 encephalopathy applied in vivo Further studies are needed to uncover the molecular mechanism that results in behavior improvements after scAAV9-mediated Gαo expression and to refine the vector design. Significance Statement GNAO1 mutations cause a spectrum of developmental, epilepsy, and movement disorders. Here, we show that intra-striatal delivery of scAAV9-GNAO1 to express the wild-type Gαo protein reduces the hyperactivity of the Gnao1 +/R209H mouse model, which carries one of the most common movement disorder-associated mutations. This is the first report of a gene therapy for GNAO1 encephalopathy applied in vivo on a patient-allele model.